Kinetics and location of poliovirus macromolecular synthesis in correlation to virus-induced cytopathology

Viral protein synthesis is found to be at a maximum before virus-induced host cell alterations can yet be detected. In our system with poliovirus type I (Mahoney) in HEp-2 cells we found this to be approximately 2.5 hr p.i. Thirty to sixty minutes later maximal viral RNA synthesis occurs which takes place exclusively in discrete areas of newly formed vacuoles. Subsequently, while still synthesizing viral RNA, the individual vacuolated centers coalesce to form an increasing mass of vacuoles so that the typical aspect of picornavirus-induced c.p.e. emerges. Thus, viral RNA synthesis, but not protein synthesis, is structurally tightly connected with the onset and increase of cytopathology.     

Modern methods of virus diagnosis

In recent years, a series of new approaches for the laboratory diagnosis of viral infections have been developed. In the present review, we describe the different tests available, such as virus isolation and identification in cell culture, antigen and genome detection, and determination of antibodies by serological methods. In order to chose the appropriate test for a given case, advantages and disadvantages of the laboratory procedures as well as their suitability for specimens taken from different organs have to be taken into account. Such considerations are particularly important for a correct interpretation of the results.     

Enterococcal meningitis in an HIV positive haemophilic patient.

A 25 year old, human immunodeficiency virus (HIV) seropositive, severe haemophilic patient was treated for suspected Pneumocystis carinii infection with high dose intravenous cotrimoxazole and subsequently with prednisolone. When he improved he was discharged on oral treatment only to return two days later, extremely unwell, with headaches, fever, sweats, tachycardia and hypotension. A lumbar puncture showed modest neutrophil pleocytosis but despite empirical antibiotic treatment with intravenous benzylpenicillin and cefuroxime he continued to deteriorate. Culture of cerebrospinal fluid subsequently grew Enterococcus faecalis that was resistant to trimethoprim and sensitive to ampicillin, rifampicin, and vancomycin. After a change in treatment to intravenous ampicillin and rifampicin he dramatically improved. Enterococcal meningitis is rare in adults but important to recognise and treat appropriately in view of its high mortality and relative resistance to antibiotics. In our case the combination of HIV infection and previous treatment with antibiotics or steroids, or both, were probable predisposing factors.